Precoding Based Cross-Tier Interference Mitigation in Centralized-RAN

This letter considers a two-tier downlink interference problem as a case of study, where macrocell user equipment (UE) shares the same frequency band with femtocell UE and suffers from severe cross-tier interference. Power control is one of the spectrally-efficient techniques used to mitigate the interference. However, it harms femtocell users since the femto base station reduces the transmitted power. In this letter, a novel scheme is proposed to jointly suppress the interference on the macrocell users, and preserve the high data rates required by femtocell users under centralized radio access network. The analytical results well agreed with the conducted simulations, and showed the superiority of the proposed scheme in achieving higher throughput compared to existing schemes.